Method and apparatus for renewing cutting edges in corn processing equipment

ABSTRACT

A method of renewing a cutting edge on a knife used in a corn cutting machine includes providing a planar knife blade with an oblique cutting edge, positioning the blade longitudinally with respect to, and at an angle to, an oncoming ear of corn and then, flexing the blade transversely to cause it to conform to a desired cutting profile, while also stiffening the blade in the direction of the oncoming ear of corn. A preferred knife blade holder and replaceable blade are also disclosed.

TECHNICAL FIELD

The invention relates to methods and apparatus for cutting and strippingcorn kernels from corn cobs, and in particular, to the cuttinginstruments used for this purpose.

BACKGROUND ART

Much of the sweet corn that is grown for human consumption is removedfrom the cob for canning and freezing while the corn kernels are still"green". Corn is considered green when the kernels are still moist andsoft and have not matured into seed.

One type of machine that is used in the food processing industry forthis purpose is shown and described in Kerr, U.S. Pat. No. 2,787,273.This machine uses six cutting instruments with curved cutting edges thatare generally positioned around a circle and around an adjustableaperture. The cutting instruments project forward from the aperture, andtogether with the aperture form what is known in the industry as an"iris". Ears of corn are shucked and then are fed endwise through theiris--small end first.

The corn cutting instruments or "knives" are unitary or integral partsthat are installed in the cutting machine. Each knife has a planar armthat reaches inward towards the center of a cylindrical cutting headwhere the iris is located. The arm is located in a plane transverse tothe longitudinal axis of each ear fed through the aperture of the iris.At the inner or working end of the arm, the knife turns parallel to theear, and presents a blade of some width that is formed concave relativeto the ear. It is known that the blade is angled upward, from heel totoe, at a certain "cob angle" from the longitudinal axis of the ear.This allows the blade to ride up the taper of the cob from the small endto the large end as the kernels are cut off.

At its free end or toe, which meets the oncoming ear of corn, the bladeis sharpened to form a curved cutting edge. The curved cutting edge ismore complex than a simple arcuate portion of a circle. The bottom ofthe blade is made concave in an arc related to a spiral cutting patharound the cob. The bottom of the blade also controls the depth of thecut so that the kernels are severed at a selected height relative to thepithy part of the cob.

It is also known that the cutting edge should attain a specified obliqueangle, which is seen in a plane that is tangent to a midpoint ofcurvature for the cutting edge. It is also known that the knives of theprior art presented an edge forming a specified "edge angle" between thetop surface of the blade and the bottom surface of the blade which rodealong the ear.

In operation of the machine, the six blades are carried by a rotatingcutting head and are spun around the ear as it passes through the iris.If one of the knives cuts too deeply, a spiral gouge will be seen on thestripped cob. This is one of the observations of the cob that isindicative of corn cutting inefficiency. The geometry of the cuttingedges relative to the corn kernels and the corn cob must be maintainedto assure a satisfactory yield of corn kernels.

After a period of use, the cutting edges become dull to the point thatthe yield of properly cut kernels drops. The current maintenanceprocedure is to remove the knives--only a small part of which isoccupied by the cutting edges--and resharpen the cutting edges. Thisresharpening requires special equipment provided by the machinemanufacturer and considerable labor for the many instances whenresharpening is necessary. The machine manufacturer also recommends thatperiodically the knives be returned to a manufactureroperated, centralsharpening facility, where the knives can be rehoned, reground andgenerally returned to an acceptable cutting profile. Even with theseprocedures, there is a further disadvantage that the blade becomesshorter with repeated resharpening and rehoning, and the original cuttinknife condition cannot be fully restored.

SUMMARY OF THE INVENTION

In the present invention the cutting edges of the corn cutter knives arerenewed by providing replaceable blades having characteristics whichmake servicing the cutter knives more convenient and less expensive thanknife resharpening, while also allowing the cutting edges of the bladesto achieve the complex positioning necessary for corn cuttingoperations.

The integral knife of the prior art is curved on both the top and thebottom, as well as presenting a curved cutting edge that tracks along adesired cutting path around an ear of corn. In contrast to the geometryof the integral knife, the replaceable blade of the present inventionhas a substantially planar body before being installed. When installed,the body is inclined at an acute angle relative to a corn feed path, andthe body of the blade is flexed transverse to the feed path to cause thecutting edge to conform to the complex final profile for a corn cuttingknife. This transverse flexing also tends to stiffen and reinforce theblade in the direction of an oncoming ear of corn.

The invention also provides a knife blade holder having an arm thatextends generally, although not exactly, in a radial direction towardthe central region of a cylindrical cutting head, where the blades willrotate in a tight circle around an ear of corn being fed endwise throughthe cutting region. There, at its inner end, each arm is provided with aclamping mechanism which includes concave and convex clamping surfacesthat hold the blade inclined at an acute angle relative to the ear ofcorn, while flexing the blade to cause the cutting edge to conform tothe desired complex cutting profile.

The invention also provides a knife blade adapted for installation inthe knife blade holder, the knife blade comprising a substantiallyplanar body that is made of steel and is relatively thin and flexible,and a cutting edge formed at a forward end of the body and disposed atan initial oblique angle relative to the transverse direction of thebody, so that when the blade is flexed the cutting edge will attain anobjective oblique angle. The body of the blade is heat treated with twoheat treatments, one to harden the blade, and another to temper theblade thereby making it more elastic and more resistant to fracture. Inthe preferred embodiment the blade is also provided with apertures thatcooperate with the holder to advantageously mount, locate, and preventrotation of the blade in the holder.

Various objects and advantages of the invention will become apparentfrom the following description and from the drawings, which form a parthereof and which are referred to in the description. The drawings anddescription relate to a preferred method and preferred devices forcarrying out the invention--and these are by way of examples of theinvention. Such examples do not, however, represent all of the methodsand devices coming within the scope of the invention, as the definitionof these has been reserved for the claims which follow the description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a portion of a corn cutting machineutilizing the method and devices of the invention;

FIG. 2 is a detail schematic diagram of a portion of FIG. 1;

FIG. 3 is a detail schematic diagram showing the operation of themachine of FIG. 1;

FIG. 4 is a sectional view taken in the plane indicated by line 4--4 inFIG. 3;

FIG. 5 is a perspective view of one of the knife assemblies seen in FIG.1;

FIG. 6 is an exploded view showing a portion of FIG. 5;

FIG. 7 is a sectional view of a first species of the embodiment of FIGS.5 and 6 taken in the plane indicated by line 7--7 in FIG. 5;

FIG. 8 is a sectional view of a second species of the embodiment ofFIGS. 5 and 6 taken in the same plane as FIG. 7;

FIG. 9 is an exploded view showing a second embodiment of the portion ofthe knife assembly shown in FIG. 6;

FIG. 10 is a sectional view of the embodiment of FIG. 9 taken in thesame plane as FIGS. 7 and 8;

FIG. 11 is a sectional view taken in the plane indicated by line 11--11in FIG. 5;

FIG. 12 is a schematic view taken in the same plane as FIG. 11;

FIG. 13 is a side elevational view of a shoe that is part of theassembly of FIG. 5;

FIG. 14 is a bottom plan view of the shoe of FIG. 13 showing the bladeof FIGS. 6, 9 and 11 installed in phantom;

FIG. 15 is a rear elevational view of the shoe of FIG. 13;

FIG. 16 is a front elevational view of the shoe of FIG. 13; and

FIG. 17 is a detail view of the blade of FIGS. 6, 9, 11 and 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is practiced with and incorporated in components used in aset of six corn cutting knives 10, which are illustrated in FIG. 1 intheir operating position within a cylindrical cutting head 11 (inphantom) of a corn cutting machine. The cutting edges of the knives 10are generally positioned around a circle and around an aperture 12 asseen best in FIG. 2. The knives 10 are adjustable relative to the centerof the aperture 12, so that the aperture can be opened up or closed downunder various operating conditions. Ears of corn, represented by the ear13 in FIG. 1, are shucked and then fed endwise--small end first--along acorn feed path, passing through the aperture and the cutting edges,which together form what is known in the industry as an "iris". Thecenter of the iris is located along the longitudinal axis 13a of the ear13 as the ear moves along the corn feed path.

The corn cutting machine may be any one of several models of corncutting machines manufactured by FMC Corporation. These include theModel 2, the Model 3AR, and the Model SC-120 corn cutter machines. Forgeneral background concerning the construction and operation of thesemachines, reference is made to Kerr, U.S. Pat. No. 2,787,273, and to thecommercial literature and service manuals available from FMCCorporation. Although the description herein shall relate to the Model 2and the Model 3AR, the teaching is applicable to the Model SC-120 aswell.

Referring now to FIG. 1 in conjunction with FIGS. 2 and 3, the cuttinghead 11 is rotated in a counterclockwise direction as ear 13 is movedlongitudinally along the corn feed path. This causes the cutting edges28 to move in spiral paths around the ear 13 as seen in FIG. 3. Theedges 28 are each disposed at an oblique angle relative to thelongitudinal axis of the ear 13 and relative to any diametrical crosssection through the ear 13. Such a cross section is illustrated as beingin the X-Y plane in FIGS. 2 and 3. When the curved cutting edge 28 isviewed in a plane tangent to a midpoint of its curvature, asapproximated by FIG. 3, it appears as a straight line that is positionedat an oblique angle OA2 relative to a diametrical cross section throughthe ear. In this example, the angle OA2 is 25°, plus or minus someallowable tolerance. With multiple cutting edges disposed at thisoblique angle OA2, kernels are stripped from the cob in overlappingspiral cutting paths, referred to as SWATH 1 and SWATH 2 in FIG. 3. Ifthe edges were perpendicular to the longitudinal axis and parallel to adiametrical cross section of the ear 13, the rotation of the edges wouldleave a spiral pattern of kernels uncut, because the narrower SWATH 1'and SWATH 2' swaths would not overlap.

Referring to FIG. 4, which is a sectional view taken in the plane of theangle OA2, the cutting path CP appears to be elliptical, because anellipse is defined by the intersection of an oblique plane and a corncob cylinder or cone. In three-dimensional space, the cutting path CP isactually a spiral of ever increasing diameter so that the curvature ofthe elliptical arc is more gently curved as the cutter progressestowards the larger end of the cob 13b.

Referring next to FIG. 5, each knife 10 is an assembly of a knife bladeholder 14 and a blade 15. The holder 14, in turn, includes a memberformed with a counterweight portion 17 at one end, a foot 19 at theother end, and a gently curving arm 18 that extends from the portion 17to the foot 19. The foot 19 is assembled to a shoe 24 to provide a bladeclamping mechanism at the inner end of the arm 18 which is to bepositioned towards the center of the cylindrical cutting head 11 in theregion of the iris as seen in FIG. 1.

Where the arm 18 meets the counterweight portion 17 of the holder memberin FIG. 5, a hole 21 is formed to pivotably mount the holder 14 withinthe cutting head 11. When the cutting head 11 of FIG. 1 is rotated, theholders 14 tend to pivot in a counterclockwise direction around theholes 21 due to the curvature and displacement of the arm 18 and thecounterweight portion 17 relative to a radius from the arm's pivot axis22 to the blade 15. The amount of actual pivoting is controlled by otherparts (not shown) of the cutting head 11 so that the curved cuttingedges 28 are pivoted from a starting minimum diameter corresponding tothe small end of the ear 13 to some maximum diameter corresponding tothe large end of the ear.

The starting minimum diameter is set in response to gauging apparatuspositioned forward of the iris in the corn cutting machine to meet andsense the size of the small end of the ear 13. The iris diameter is setto the diameter of the small end if the cob 136 plus an additionalradial increment that produces the desired depth of cut along thecutting path CP, as shown in FIG. 4. The depth of cut is the height atwhich the kernels 13c are severed from the cob 13b. As the ear 13 movesthrough the iris, the cutting edges 28 are forced to a position ofincreasing radius from the center of the iris, until they reach thepoint where they allow the largest diametrical cross section of the corncob 13b to pass.

With the holders 14 mounted in their operating position seen in FIG. 1,the arms 18 extend generally, but not exactly, radially inward towardsthe iris. The arms 18 are substantially planar, i.e., they are disposedin a plane transverse to the corn feed path. Because they have athickness they are also disposed in several other adjacent transverseplanes. In this instance, a "transverse" plane is one that is normal tothe longitudinal axis of the ear of corn and to the corn feed path. Eachholder 14 turns from the transverse plane of the arm 18 into anintegrally formed foot 19 that runs longitudinally with respect to thecorn feed path and the longitudinal axis of an oncoming ear of corn.

Referring next to FIGS. 6 and 9, two species of blade clampingmechanisms for securing the blade 15 in position are shown. The twomechanisms differ in the way they prevent the blade 15 from rotatingaround an axis of fastening provided by fastener 42. In FIG. 6 the foot19 forms a concave blade clamping surface 23 to contact the top side ofthe blade 15. A wedge-shaped shoe 24, on the other side of the blade 15in FIG. 6, forms a convex blade clamping surface 25 to contact thebottom side of the blade 15. It will be seen in FIGS. 11 and 12 thatthese two surfaces 23 and 25 are elevated at the rear of the foot 19 andshoe 24 to position the blade 15 at an acute angle relative to the cornfeed path and the longitudinal axis of an oncoming ear of corn. Thisacute "attack angle" is calculated by subtracting a "cob angle" shown inFIG. 12 from an overall edge angle that was utilized in a knife of theprior art having an integrally formed cutting blade. The "cob angle" isthe angle at which the concave surface 26 of the shoe 24 that faces andengages the cob 13b is oriented relative to the corn feed path and tothe longitudinal axis 13a of an oncoming ear of corn 13.

Referring again to FIGS. 6 and 9, the blade 15 has a substantiallyplanar, elongated body with apertures 41, 43 and 46 in FIG. 6, and withapertures 41 and 46 in FIG. 9. The centers of the apertures 41 and 46are located along a longitudinal axis 32 for the blade 15, and thecenter of aperture 43 is also located on this axis. It will becomeapparent from the following description that these apertures 41, 43 and46 could also be located on either side of this longitudinal axis 32.They are described here as being on the axis to assist the location ofthis axis in the drawings.

The blade 15 may be made of (1) a high to medium carbon steel, (2) ahigh to medium carbon low alloy steel (3) tool steel, or (4) stainlesssteel. The preferred material is a high carbon steel designated AISIC-1095. The blade 15 is made relatively thin--so that it can beflexed--and the term "thin" as related to the blade shall mean athickness dimension in a range from 0.005 inch to 0.025 inch inclusive.The preferred thickness dimension for the blade 15 is from 0.011 inch to0.013 inch inclusive. Preferably the blades are mass produced in strips,from which the blades are separated. The blades are treated with twoheat treatments. In one of these, the blade strips are heated to arelatively higher temperature and then quenched to harden the blades. Inthe other, the blade strips are heated to an elevated, yet relativelylower temperature, and then quenched to impart tempering and elasticity.

At the forward end of its body 27, the blade 15 is angled at an initialoblique angle OA2 of approximately 23.5° (allowing for some tolerance),which is shown in FIG. 6 relative to a transverse axis 33 that isorthogonal to the longitudinal blade axis 32. The initial oblique angleOA1 is selected so that when the blade 15 is flexed, it will attain theobjective oblique angle OA2 shown in FIGS. 3 and 14. As seen in FIG. 17,the cutting edge 28 is preferably flat along the top side of the blade15 with a bevel 35 provided along the bottom side. The length of thebeveled region should be from 1/16 inch to 1/32 inch inclusive for bestresults. For the preferred thickness of the blade 15, this results in apreferred bevel angle A3 of approximately 16° between the top and bottomsides adjacent the edge 28.

Referring now to FIGS. 6, 9 and 11, the blade 15 is mounted in theholder 14 by inserting it between the blade clamping surfaces 23, 25with the apertures 41, 43 and 46 in the blade 15 positioned to properlylocate the blade 15 relative to the foot 19 and the shoe 24. A fastener42--in this instance, a screw--is inserted through a screw guide hole 38in the foot 19, through the large aperture 41 in the blade 15, and intoa tapped hole 39 in the shoe 24, where it threadingly engages the shoe24. The assembly is secured by turning the screw 42 to draw the convexsurface 25 of the shoe 24 upward against the blade 15 and then theconcave surface 23 of the foot 19, as seen in FIG. 7, 8 and 10, whichcauses the blade 15 to flex in a direction transverse to itslongitudinal axis 32 and to conform to the curvature of thecomplementary blade clamping surfaces 23, 25.

FIG. 7 illustrates a species of the blade clamping mechanism applicableto the FMC Model 3A corn cutter where a radius from a pivot axis 22 forthe arm is tangent to the near side of the blade 15. FIGS. 8 and 10illustrate the blade clamping mechanisms of FIGS. 6 and 9 as applied tothe FMC Model 2 corn cutter where the radial reference for the arm istangent to the midpoint of curvature of the blade 15.

It is good machine design practice to make the mounting aperture 41substantially larger in diameter than the screw 42. When this practiceis followed the blade 15 may tend to rotate around the axis of the screw42, so in FIG. 6 two additional pins 44 are positioned to project fromthe concave blade clamping surface 23 through more closely fittingapertures 43 and 46 in the blade 15 and into corresponding holes 48 inthe shoe 24. This provides two additional points at which the blade 15is secured, and this prevents rotation of the blade 15 around thefastener 42.

Besides preventing rotation, the pins 44 and apertures 43, 46 are alsoimportant in locating the cutting edge 28 of the blade 15 to control itsprojection beyond the leading edges 29, 30 of the foot 19 and shoe 24,respectively. The leading edges 29, 30 are designed to run parallel tothe cutting edge 28 of the blade 15 as will be described in more detailbelow. The pins 44 are located so as to cause the cutting edge 28 toproject approximately 1/8 inch forward of the leading edges 29, 30 alongits entire length. This provides the best support of blade 15, whilelimiting entry of cuttings in between the blade 15 and the clampingsurfaces 23 and 25.

Referring to FIG. 9, a second species of the nonrotation mechanism isprovided by forming side rails 31 along opposite sides of the concaveblade clamping surface 23 to further form a blade receiving channel.When the blade 15 is positioned in this channel and fastened in place bythe screw 42, the side rails 31 will prevent rotation of the blade 15 onthe blade clamping surfaces 23 and 25. A single pin 44 projects from theconcave blade clamping surface 23 through aperture 46 and into the shoe24 to locate the cutting edge 28 relative to the leading edges 29, 30 asdescribed for the first species.

The method of the invention is advantageous in allowing the use of asubstantially planar, replaceable blade 15, and yet producing a corncutter knife 10 with a cutting edge 28 that attains the complex profileof the prior art integral cutter knives. To carry out the method of theinvention, the blade 15 is made as described above so that it isflexible in a direction transverse to a longitudinal blade axis 32 andhas a cutting edge 26 angled at an oblique angle relative to thetransverse direction of the blade body 28. The blade 15 is positioned inthe holder 14 with its longitudinal blade axis 32 forming the acute"attack angle" relative to the longitudinal axis 13a of an ear of corn13 moving longitudinally through the machine. The blade body 28 is thenflexed by the assembly procedure described earlier to cause the cuttingedge 26 to conform to the desired curved profile.

Referring to FIGS. 11-16, the shape of the concave surface 23 on thefoot 19 and the shape of the surfaces 25, 26 on the shoe, as well as theline of the leading edges 29, 30, is determined by various aspects ofcorn cutter and corn geometry. It is well known that ears of corn, aswell as corn cobs, are tapered. It has been found that corn exhibitssome average or typical taper, which is identified in FIG. 12 as the"cob angle". If the envelope of the cob 13b were extended it woulddefine a cone. The bottom surface of the corn cutter knives of the priorart was inclined along a longitudinal axis at the cob angle, and thiscob angle can be measured for any particular knife, or it can bedetermined from a statistical sample of corn ears. The bottom surface 26on the shoe 24 of the present holder 14 is, therefore, inclined at thisangle so as to ride up the cob as well as around it in a wideningspiral. Because the cob angle is typically very acute, however, thecurvature of the surface 26 is based on a cylinder tilted at the cobangle rather than a cone. The radius of this theoretical cylinder isselected so that the shoe 24 will a along an acceptable spiral cuttingpath for ears of the size typically processed by the machine. Thisradius can be measured on the integral corn cutter knives of the priorart.

As explained earlier, the integral knives of the prior art formed acutting edge angle between this bottom surface 26 and the top surface ofwhat is now the foot 19. In the present invention, the clamping surfaces23, 25 are formed to hold the blade body 27 with the longitudinal bladeaxis positioned at this former cutting edge angle. The angle of theblade axis is also related to a line parallel to the corn axis and tothe corn feed path, and this angle is identified in FIG. 12 as the"attack angle".

Once the blade body 27 has been elevated to a selected attack angle,then its amount of flexing in the transverse direction is calculated byfinding an intersection between a portion of a "blade cylinder" definingthe surface 23 and the cob cylinder. Referring to FIG. 12, the bladecylinder and the cob cylinder have been selected to intersect at anangle equivalent to the edge angle of the integral knife of the priorart. For one such integral knife that edge angle was approximately 10°.The intersection of cylinders is determined as a line intersection whichdefines the cutting edge, which when viewed from the appropriate plane,achieves the desired, or objective oblique angle--in this example25°--of the cutting edge relative to a diametrical cross section of anear of corn.

The resolution of this problem defines a cylindrical surface 23 with asomewhat smaller radius than the radius R1 of the corn cylinder (whichdefines surface 26). This smaller radius of surface 23 is slightlygreater, by the thickness of the blade, than the radius R2 of surface 25which is illustrated in FIG. 16. The centers for the radii defining thesurfaces 23 and 25 coincide, and are offset in a transverse directionfrom the center of the corn cylinder and from leading side 34 of thefoot 19 and the shoe 24 as shown in FIG. 16. Since the convex topsurface 25 is defined by this smaller radius R2, it is more curved thanthe bottom surface 26. Remembering that the initial oblique angle OAI ofthe blade was less than 25° when the blade was planar, it can be seenthat flexing the blade body 27 (seen in phantom in FIG. 14) increasesslightly the oblique angle of the cutting edge 28 to OA2 as the width ofthe blade is narrowed, and this change of angle must be considered inmaking the blade 15.

Besides attaining the desired cutting edge profile, the flexing of theplanar blade 15 in the transverse direction provides resistance tobending in the longitudinal direction. This, along with the support ofthe blade to within approximately 1/8 inch of its cutting edge, and heattreating the blade to temper it and make it more elastic and lessbrittle, are factors which contribute to extend the time betweenreplacements of the blade.

It should be understood that many of the details related herein havebeen by way of example, and other ways to practice the method or to makethe implements of the invention will be apparent to those skilled in theart, as well as equivalent methods and implements, and that these alsoare considered to be within the scope of the invention to the extentthey come within the scope of the following claims.

I claim:
 1. A method of renewing a cutting edge of a knife of a typeused in a machine for cutting corn kernels from a corn cob, the methodcomprising:providing a knife blade having a substantially planar bodywhich is formed along a blade axis to be disposed longitudinally withrespect to an ear of corn moving longitudinally through the machine andwhich is flexible in a direction transverse to the axis, the knife bladealso having at a forward end of the body an oblique cutting edge that isdisposed at an oblique angle relative to the transverse direction of thebody and the knife blade having a rear end; positioning the knife bladein a knife blade holder with the blade axis of the body elevated at therear end of the body to form an acute angle with a longitudinal axis ofan ear of corn moving longitudinally through the machine; and flexingthe body transverse to its blade axis to cause the oblique cutting edgeto conform to a curved profile for cutting a spiralling swath ofsufficient width along the corn cob.
 2. The method of claim 1,wherein:the cutting edge is disposed at an inital oblique angle relativeto the transverse direction of the body; and wherein the flexing stepincludes flexing the cutting edge to conform to a curve while attainingan objective oblique angle of the cutting edge relative to a crosssection of the ear of corn.
 3. The method of claim 1, wherein theflexing step includes flexing the cutting edge to conform to a curvesubstantially defined by a portion of an ellipse.
 4. The method of claim1, wherein the positioning step includes positioning the knife blade ina knife blade holder with the blade axis of the body coinciding with anangle of attack for the cutting edge relative to a longitudinal axis ofan ear of corn moving longitudinally through the machine.
 5. The methodof claim 1, further comprising the step of supporting the body of theknife blade to within approximately 1/8 inch of the cutting edge forimproved performance.
 6. A knife blade holder adapted to hold a flexibleand substantially planar blade with a cutting edge on one end so as toencounter an oncoming longitudinally oriented ear of corn that is fedthrough a rotatable cutting head in a corn processing machine, the knifeblade holder comprising:an arm extending from an outer end adapted formounting the knife blade holder to the cutting head to an inner endadapted for positioning towards the center of the cutting head, the armbeing adapted to extend transversely to the oncoming ear of corn; and aclamping mechanism on the inner end of the arm, wherein the clampingmechanism includes opposing concave and convex blade clamping surfaceswhich, when the knife blade holder is installed in the corn processingmachine, said blade clamping surfaces are disposed longitudinally withrespect to, and inclined from front to rear at an acute angle to, alongitudinally oriented ear of corn that is fed through the cornprocessing machine; and wherein the concave and convex blade clampingsurfaces are formed to flex the blade transverse to the longitudinallyoriented ear of corn that is fed through the corn processing machinewhen the clamping mechanism is closed, to case the cutting edge toconform to a curved profile for cutting a spiralling swath of sufficientwidth along the ear of corn.
 7. The knife blade holder of claim 6further adapted to hold a blade having a cutting edge disposed at anoblique angle relative to a transverse direction of the blade, andwherein the concave and convex blade clamping surfaces are formed toflex the blade to cause the cutting edge to conform to a curvesubstantially defined by a portion of an ellipse.
 8. The knife bladeholder of claim 6 further adapted to hold a blade having a cutting edgedisposed at an initial oblique angle relative to a transverse directionof the blade, and wherein the concave and convex blade clamping surfacesare formed to flex the blade to cause the cutting edge to curve whileattaining an objective oblique angle of the cutting edge relative to across section of the ear of corn.
 9. The knife blade holder of claim 6wherein the concave and convex blade clamping surfaces are formed toposition the blade so that a longitudinal axis of the blade coincideswith an angle of attack for the cutting edge relative to a longitudinalaxis of an ear of corn moving longitudinally through the machine. 10.The knife blade holder of claim 6 wherein:the clamping mechanismincludes a first clamping member formed as an integral extension fromthe arm, wherein the first clamping member is disposed longitudinallywith respect to the oncoming ear of corn, and wherein the first clampingmember forms the concave clamping surface to face towards a passing earof corn; and wherein the clamping mechanism includes a second clampingmember that is formed as a detachable shoe with the convex clampingsurface that faces away from a passing ear of corn when the shoe isattached to the first clamping member.
 11. The knife blade holder ofclaim 6, wherein the clamping mechanism also forms means extendingbetween the blade clamping surfaces and cooperable with the blade forpreventing the blade from rotating while being held between the bladeclamping surfaces.
 12. The knife blade holder of claim 6, wherein theclamping mechanism also forms location means cooperable with the bladeto locate the blade in the knife blade holder with the cutting edgeprojecting approximately 1/8 inch from the knife blade holder along afull length of the cutting edge.
 13. A method of renewing a cutting edgeof a knife of a type used in a machine for cutting corn kernels from acorn cob, the method comprising:securing a blade to a concave supportsurface formed as part of the corn cutter knife and roughly defining aportion of a cylinder extending longitudinally at a selected angle tothe cob from which the corn kernels are to be cut, the blade having abody that is made of a resilient, flexible material and further having acutting edge having a bevel, the cutting edge being formed at a selectedangle to a longitudinal axis of the body; and causing the blade toconform to the curved shape of the blade support surface with the bevellocated on the concave side of the blade body and the cutting edge heldat a selected angle to the cob.
 14. A corn cutter knife adapted to holda resilient, flexible, thin blade and to be used in a mechanical corncutter, the corn cutter knife comprising:(a) an arm extending generallyparallel to a plane and adapted to be pivotably attached at a selectedpoint to the corn cutter; and (b) a blade clamp attached to the arm at alocation remote from the arm's point of pivotable attachment to the corncutter, the blade clamp including a foot and a shoe, the foot beingrigidly attached to the arm and having a curved blade clamping surfacedefining approximately a portion of the surface of a cylinder, and theshoe being removably attachable to the foot and adapted to removablyforce and secure the blade against the blade clamping surface, causingit to conform to the curved shape thereof; whereupon the blade may beremovably mounted in the knife with a fixed and predeterminable curvedconfiguration imparted thereto.
 15. A knife blade holder adapted to holda flexible and substantially planar blade with a cutting edge on one endso as to encounter an oncoming longitudinally oriented ear of corn thatis fed through a rotatable cutting head in a corn processing machine,the knife blade holder comprising:an arm extending from an outer endadapted for mounting the knife blade holder to the cutting head to aninner end adapted for positioning towards the center of the cuttinghead, the arm being adapted to extend transversely to the oncoming earof corn; and a clamping mechanism on the inner end of the arm, whereinthe clamping mechanism includes opposing concave and convex bladeclamping surfaces having blade locating means including a pincooperating with a hole in the blade which, when the knife blade holderis installed in the corn processing amchine, said blade clampingsurfaces are disposed longitudinally with respect to, and inclined fromfront to rear at an acute angle to, a longitudinally oriented ear ofcorn that is fed through the corn processing machine; wherein theconcave and convex blade clamping surfaces are formed to flex the bladetransverse to the longitudinally oriented ear of corn that is fedthrough the corn processing machine when the clamping mechanism isclosed, to cause the cutting edge to conform to a curved profile forcutting a spiralling swath of sufficient width along the ear of corn;and said clamping mechanism further including blade orienting means toorient the blade in a fixed and particular relationship to the bladeclamping surface, comprising at least one of the clamping surfaces beingformed on a wedge shaped clamping element having a narrow and widesections relative to the longitudinal length of the element, the narrowsection of the clamping element oriented toward the cutting edge of theblade when the clamping surfaces and the blade are clamped together; theother clamping surface including side channels between which the bladeis seated.